PGP and breast cancer: However, in our previous studies [18], we transdifferentiated MDA-MB 231 breast cancer cells into osteoblast-like cells by embedding them into a stiff hydrogel, and a decreased expression of multidrug resistance glycoprotein P (Pgp) with an increased sensitization to doxorubicin was found for osteoblast-like cells compared to untransdifferentiated cells [18].